Inside Unmanned Systems

AUG-SEP 2018

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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AIR HAZARD LOCATION
62 August/September 2018 unmanned systems
inside
In addition, "the workers have to wear suits
w ith visors and closed breathing systems,"
Whittaker said. "Until you've operated in those
things, it's hard to describe the challenges with
visibility and manipulation with gloves you face,
and depending on the weather conditions, how
hot and confining they are."
Instead, RadPiper will find these radioactive
deposits by traveling inside the pipes. "By taking
measurements directly inside the pipe, all these
considerations regarding attenuation are not an
issue," Rimando said. "And RadPiper can scan as
it moves continuously without stopping. The rea-
son people have to stop when scanning from the
outside is because they have to wait for measure-
ments to come in since a pipe can weaken signals
traveling through it, but by scanning within the
pipe, RadPiper avoids that concern. It is much
more efficient."
RadPiper is a tetherless robot designed to move
on a pair of f lexible tracks like a miniature tank
or bulldozer. "Going tetherless gives the robot a
lot of freedom to operate," Rimando said.
Tethered robots have a decades-long history of
use in nuclear facilities. Tethers can offer virtu-
ally unlimited power as well as wires for commu-
nications. And a tether can serve as a leash to help
winch a robot back if necessary.
However, "in the types of environments we are
sending robots, one concern is that the tether
can be severed or even simply disconnected, and
then that's a real pickle—you'll lose communi-
cations, you'll lose control and you'll lose your
recovery capabilities," Rimando said. "Also, in
areas with radioactive contamination, the teth-
ers can disturb those contaminants and spread
them, and when you're dealing with fissile mate-
rials, you don't want that material to accumulate
and raise concerns it might go critical. Advances
in robotics, batteries, wireless communications
and microprocessors now help give tetherless
systems a lot of capabilities."
RadPiper is about 45 inches long by 17 inches
wide and 21 inches tall, and weighs approximately
180 lbs. Sensors in its tracks help measure the
distance it has traveled, and an inertial measure-
ment unit (IMU) and laser rangefinder help the
robot stay upright and keep track of its position.
RadPiper is equipped with a fanless embedded
Intel quad-core i7 system as its main computer.
The robot is equipped with two LiDAR range-
finders, a fisheye camera, eight white ultraviolet
LEDs to help it see obstructions such as closed
valves, and eight ultraviolet LEDs that can make
uranium-loaded deposits visibly f luoresce. After
scanning a stretch of pipe, RadPiper automati-
cally returns to its launch point.
The robot's Canberra Osprey radiation detec-
tor uses a standard sodium iodide sensor to count
gamma rays. The sensor is positioned between
two large lead disks that block gamma rays from
radioactive deposits that may lie beyond the one-
foot section of pipe the sensor is scanning at any
given time. "These lead disks let you know what
exactly the robot measured from a given slice of
the pipe, without having to worry about interfer-
ence from elsewhere in the pipe," Whittaker said.
A USB data drive is used to store data from
each run and transfer it to a computer. Analyzing
the data is an automated process that takes a few
minutes on a laptop, and the results include a
chart of deposits plotted with respect to distance
inside the pipe, as well as visual imagery.
A pair of lithium iron magnesium phosphate
battery modules can help the robot operate for
five hours and a maximum total round trip of 600
feet. Battery charging time is typically two hours,
allowing for rapid turnaround.
To help prevent nuclear waste from cling-
ing onto RadPiper, the robot's contours are as
round as possible, Rimando said. After RadPiper
emerges from a pipe, researchers wipe off any
contamination on the robot.
RADIION
CLEANUP
" OUR FINAL GOAL IS A SYSTEM
OF SYSTEMS, WHERE MULTIPLE ROBOTS CAN ACCESS
UNDERGROUND ENVIRONMENTS, MAP THEM, AND ANNOTATE
THESE MAPS WITH RADIATION MEASUREMENTS."
Kostas Alexis, head of the Autonomous Robots Lab, University of Nevada-Reno